1. Field of the Invention
The invention relates to a hydraulic system for actuating a continuously variable belt-driven conical-pulley transmission having two conical pulleys encircled by an endless torque-transmitting means, each of which comprises two conical disks, one of which is axially movable depending on the pressure in an associated pressing chamber; and having a torque sensor which includes a torque sensing chamber that is connected to a hydraulic energy source and is linked with the pressing chambers.
2. Description of the Related Art
A belt-driven conical-pulley transmission with a torque sensor is known from German published unexamined application DE 42 34 294 A1 which is designed as a valve controlled by transmission ratio and torque, and which transmits the torque directly from the input-side pulley to the output-side pulley. A torque-sensing device for a belt-driven conical-pulley transmission is known from international publication WO 2007/110026 A1 which includes ramp surfaces with a gradient that decreases with increasing distance from its lowest point in such a way that the quotient of clamping pressure and torque is essentially independent of the positions of the ramp surfaces and the guide surface relative to each other.
The object of the invention is to create a hydraulic system according to the preamble of Claim 1, by which the torque-dependent and transmission-ratio-dependent axial clamping of the axially movable conical disks is optimized. At the same time, the clamping pressure in the pressing chambers should in particular not depend on the speed of rotation.